Publications by authors named "Shin-Hong Shiao"

13 Publications

  • Page 1 of 1

A Thioester-Containing Protein Controls Dengue Virus Infection in Through Modulating Immune Response.

Front Immunol 2021 13;12:670122. Epub 2021 May 13.

Department of Tropical Medicine and Parasitology, College of Medicine, National Taiwan University, Taipei, Taiwan.

Complement-like proteins in arthropods defend against invading pathogens in the early phases of infection. Thioester-containing proteins (TEPs), which exhibit high similarity to mammalian complement C3, are thought to play a key role in the innate immunity of arthropods. We identified and characterized anti-dengue virus (DENV) host factors, in particular complement-like proteins, in the mosquito . Our results indicate that TEP1 limits DENV infection in We showed that transcription is highly induced in mosquitoes following DENV infection. Silencing resulted in the up-regulation of viral RNA and proteins. In addition, the production of infectious virus particles increased in the absence of . We generated a transgenic mosquito line with a TEP1 loss-of-function phenotype under a blood meal-inducible promoter. We showed that viral protein and titers increased in transgenic mosquitoes after an infectious blood meal. Interestingly, expression of transcription factor Rel2 and certain anti-microbial peptides (AMPs) were inhibited in transgenic mosquitoes. Overall, our results suggest that TEP1 regulates the immune response and consequently controls the replication of dengue virus in mosquitoes. This finding provides new insight into the molecular mechanisms of mosquito host factors in the regulation of DENV replication.
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http://dx.doi.org/10.3389/fimmu.2021.670122DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC8155531PMC
May 2021

A simplified method for blood feeding, oral infection, and saliva collection of the dengue vector mosquitoes.

PLoS One 2020 29;15(5):e0233618. Epub 2020 May 29.

Department of Entomology, College of Agriculture and Natural Resources, National Chung Hsing University, Taichung, Taiwan.

A simple device using folded Parafilm-M as an artificial blood feeder was designed for studying two important dengue vector mosquitoes, Aedes aegypti and Aedes albopictus. The efficiency of the artificial blood feeder was investigated by comparing the numbers of engorged mosquitoes that fed on the artificial blood feeder versus mice as a live blood source. Significantly more engorged females Aedes aegypti fed on the artificial blood feeder than on mice. In addition, the artificial feeder could serve as a useful apparatus for oral infection via artificial blood meals, and for saliva collection in mosquitoes. Our method enabled us to collect saliva from multiple mosquitoes at once, providing sufficient infected saliva for determination of the virus titer by plaque assay analysis. Our artificial feeder has the advantage that it is simple, inexpensive, and efficient.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0233618PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7259494PMC
August 2020

A salivary protein of Aedes aegypti promotes dengue-2 virus replication and transmission.

Insect Biochem Mol Biol 2019 08 29;111:103181. Epub 2019 Jun 29.

Department of Tropical Medicine and Parasitology, College of Medicine, National Taiwan University, Taipei, Taiwan. Electronic address:

Although dengue is the most prevalent arthropod-borne viral disease in humans, no effective medication or vaccine is presently available. Previous studies suggested that mosquito salivary proteins influence infection by the dengue virus (DENV) in the mammalian host. However, the effects of salivary proteins on DENV replication within the Aedes aegypti mosquito remain largely unknown. In this study, we investigated the effect of a specific salivary protein (named AaSG34) on DENV serotype 2 (DENV2) replication and transmission. We showed that transcripts of AaSG34 were upregulated in the salivary glands of Aedes aegypti mosquitoes after a meal of blood infected with DENV2. Transcripts of the dengue viral genome and envelop protein in the salivary glands were significantly diminished after an infectious blood meal when AaSG34 was silenced. The effect of AaSG34 on DENV2 transmission was investigated in Stat1-deficient mice. The intradermal inoculation of infectious mosquito saliva induced hemorrhaging in the Stat1-deficient mice; however, saliva from the AaSG34-silenced mosquitoes did not induce hemorrhaging, suggesting that AaSG34 enhances DENV2 transmission. This is the first report to demonstrate that the protein AaSG34 promotes DENV2 replication in mosquito salivary glands and enhances the transmission of the virus to the mammalian host.
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http://dx.doi.org/10.1016/j.ibmb.2019.103181DOI Listing
August 2019

Novel phthalocyanines activated by dim light for mosquito larva- and cell-inactivation with inference for their potential as broad-spectrum photodynamic insecticides.

PLoS One 2019 29;14(5):e0217355. Epub 2019 May 29.

Department of Microbiology/Immunology, Chicago Medical School/Rosalind Franklin University of Medicine & Science, North Chicago, IL, United States of America.

Mosquitoes are significant vectors, responsible for transmitting serious infectious diseases, including the recent epidemics of global significance caused by, for example, Zika, Dengue and Chikungunya viruses. The chemical insecticides in use for mosquito control are toxic and ineffective due to the development of resistance to them. The new approach to reduce mosquito population by releasing genetically modified males to cause female infertility is still under environmental safety evaluation. Photodynamic insecticides (PDI) have long been known as a safe and effective alternative by using dyes as the photosensitizers (PS) for activation with light to generate insecticidal singlet oxygen and reactive oxygen species. This approach warrants re-examination with advances in the chemical synthesis of novel PS, e.g. phthalocyanines (PC). Nine PC were compared with five porphyrin derivatives and two classic PS of halogenated fluoresceins, i.e. cyanosine and rose bengal experimentally for photodynamic treatment (PDT) of the larvae of laboratory-reared Aedes mosquitoes and their cell lines. Groups of 2nd instar larvae were first exposed overnight to graded concentrations of each PS in the dark followed by their exposure to dim light for up to 7 hours. Larvae of both experimental and control groups were examined hourly for viability based on their motility. Monolayers of mosquito cells were similarly PS-sensitized and exposed briefly to light at the PS-specific excitation wavelengths. Cell viability was assessed by MTT reduction assays. Of the 16 PS examined for photodynamic inactivation of the mosquito larvae, effective are three novel PC, i.e. amino-Si-PC1 and -PC2, anilinium Zn-PC3.4, pyridyloxy Si-PC14 and two porphyrin derivatives, i.e. TPPS2 and TMAP. Their EC50 values were determined, all falling in the nanomolar range lower than those of rose bengal and cyanosine. All PS effective in vivo were also found to dose-dependently inactivate mosquito cells photodynamically in vitro, providing cellular basis for their larvicidal activities. The present findings of novel PC with effective photodynamic larvicidal activities provide fresh impetus to the development of PDI with their established advantages in safety and efficacy. Toward that end, the insect cell lines are of value for rapid screening of new PC. The optimal excitability of PC with insect-invisible red light is inferred to have the potential to broaden the range of targetable insect pests.
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http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0217355PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6541276PMC
February 2020

The non-canonical Notch signaling is essential for the control of fertility in Aedes aegypti.

PLoS Negl Trop Dis 2018 03 5;12(3):e0006307. Epub 2018 Mar 5.

Department of Parasitology, National Taiwan University, Taipei, Taiwan.

The Notch signaling pathway is a highly evolutionarily-conserved cell-cell signaling pathway that regulates many events during development. It plays a pivotal role in the regulation of fundamental cellular processes, such as cell proliferation, stem cell maintenance, and differentiation during embryonic and adult development. However, functions of Notch signaling in Aedes aegypti, the major mosquito vector for dengue, are largely unknown. In this study, we identified a unique feature of A. aegypti Notch (AaNotch) in the control of the sterile-like phenotype in female mosquitoes. Silencing AaNotch with a reverse genetic approach significantly reduced the fecundity and fertility of the mosquito. Silencing AaNotch also resulted in the prevention of micropyle formation, which led to impaired fertilization. In addition, JNK phosphorylation (a signaling molecule in the non-canonical Notch signaling pathway) was inhibited in the absence of AaNotch. Furthermore, treatment with a JNK inhibitor in the mosquito resulted in impaired fecundity and fertility. Taken together, our results demonstrate that non-canonical Notch signaling is essential for controlling fertility in the A. aegypti mosquito.
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http://dx.doi.org/10.1371/journal.pntd.0006307DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5854436PMC
March 2018

A case of human infection with Anisakis simplex in Taiwan.

Gastrointest Endosc 2015 Oct 9;82(4):757-8; discussion 758. Epub 2015 May 9.

Department of Internal Medicine, National Taiwan University Hospital, Taipei, Taiwan.

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http://dx.doi.org/10.1016/j.gie.2015.03.1983DOI Listing
October 2015

Frizzled 2 is a key component in the regulation of TOR signaling-mediated egg production in the mosquito Aedes aegypti.

Insect Biochem Mol Biol 2015 Jun 15;61:17-24. Epub 2015 Apr 15.

Department of Parasitology, National Taiwan University, Taipei, Taiwan. Electronic address:

The Wnt signaling pathway was first discovered as a key event in embryonic development and cell polarity in Drosophila. Recently, several reports have shown that Wnt stimulates translation and cell growth by activating the mTOR pathway in mammals. Previous studies have demonstrated that the Target of Rapamycin (TOR) pathway plays an important role in mosquito vitellogenesis. However, the interactions between these two pathways are poorly understood in the mosquito. In this study, we hypothesized that factors from the TOR and Wnt signaling pathways interacted synergistically in mosquito vitellogenesis. Our results showed that silencing Aedes aegypti Frizzled 2 (AaFz2), a transmembrane receptor of the Wnt signaling pathway, decreased the fecundity of mosquitoes. We showed that AaFz2 was highly expressed at the transcriptional and translational levels in the female mosquito 6 h after a blood meal, indicating amino acid-stimulated expression of AaFz2. Notably, the phosphorylation of S6K, a downstream target of the TOR pathway, and the expression of vitellogenin were inhibited in the absence of AaFz2. A direct link was found in this study between Wnt and TOR signaling in the regulation of mosquito reproduction.
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http://dx.doi.org/10.1016/j.ibmb.2015.03.010DOI Listing
June 2015

AaCAT1 of the yellow fever mosquito, Aedes aegypti: a novel histidine-specific amino acid transporter from the SLC7 family.

J Biol Chem 2011 Mar 24;286(12):10803-13. Epub 2011 Jan 24.

Department of Biology and Institute of Applied Biosciences, New Mexico State University, Las Cruces, New Mexico 88003-8001, USA.

Insect yolk protein precursor gene expression is regulated by nutritional and endocrine signals. A surge of amino acids in the hemolymph of blood-fed female mosquitoes activates a nutrient signaling system in the fat bodies, which subsequently derepresses yolk protein precursor genes and makes them responsive to activation by steroid hormones. Orphan transporters of the SLC7 family were identified as essential upstream components of the nutrient signaling system in the fat body of fruit flies and the yellow fever mosquito, Aedes aegypti. However, the transport function of these proteins was unknown. We report expression and functional characterization of AaCAT1, cloned from the fat body of A. aegypti. Expression of AaCAT1 transcript and protein undergoes dynamic changes during postembryonic development of the mosquito. Transcript expression was especially high in the third and fourth larval stages; however, the AaCAT1 protein was detected only in pupa and adult stages. Functional expression and analysis of AaCAT1 in Xenopus oocytes revealed that it acts as a sodium-independent cationic amino acid transporter, with unique selectivity to L-histidine at neutral pH (K(0.5)(L-His) = 0.34 ± 0.07 mM, pH 7.2). Acidification to pH 6.2 dramatically increases AaCAT1-specific His(+)-induced current. RNAi-mediated silencing of AaCAT1 reduces egg yield of subsequent ovipositions. Our data show that AaCAT1 has notable differences in its transport mechanism when compared with related mammalian cationic amino acid transporters. It may execute histidine-specific transport and signaling in mosquito tissues.
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http://dx.doi.org/10.1074/jbc.M110.179739DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3060531PMC
March 2011

Juvenile hormone connects larval nutrition with target of rapamycin signaling in the mosquito Aedes aegypti.

J Insect Physiol 2008 Jan 2;54(1):231-9. Epub 2007 Oct 2.

Department of Entomology and the Institute for Integrative Genome Biology, University of California, Riverside, California, Watkins Drive, CA 92521, USA.

Anautogenous mosquitoes require blood meals to promote egg development. If adequate nutrients are not obtained during larval development, the resulting "small" sized adult mosquitoes require multiple blood meals for egg development; markedly increasing host-vector contacts and the likelihood of disease transmission. Nutrient-sensitive target of rapamycin (TOR) signaling is a key signaling pathway that links elevated hemolymph amino acid levels derived from the blood meal to the expression of yolk protein precursors in the fat body. Here we report that the blood-meal-induced activation of the TOR-signaling pathway and subsequent egg maturation depends on the accumulation of adequate nutritional reserves during larval development. We have established well-nourished, "standard" mosquitoes and malnourished, "small" mosquitoes as models to address this nutrient sensitive pathway. This regulatory mechanism involves juvenile hormone (JH), which acts as a mediator of fat body competence, permitting the response to amino acids derived from the blood meal. We demonstrate that treatment with JH results in recovery of the TOR molecular machinery, Aedes aegypti cationic amino acid transporter 2 (AaiCAT2), TOR, and S6 kinase (S6K), in fat bodies of small mosquitoes, enabling them to complete their first gonotrophic cycle after a single blood meal. These findings establish a direct link between nutrient reserves and the establishment of TOR signaling in mosquitoes.
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http://dx.doi.org/10.1016/j.jinsphys.2007.09.007DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2242809PMC
January 2008

Forkhead transcription factors regulate mosquito reproduction.

Insect Biochem Mol Biol 2007 Sep 24;37(9):985-97. Epub 2007 May 24.

Department of Entomology and the Institute for Integrative Genome Biology, University of California-Riverside, Watkins Drive, Riverside, CA 92521, USA.

Forkhead-box (Fox) genes encode a family of transcription factors defined by a 'winged helix' DNA-binding domain. In this study we aimed to identify Fox factors that are expressed within the fat body of the yellow fever mosquito Aedes aegypti, and determine whether any of these are involved in the regulation of mosquito yolk protein gene expression. The Ae. aegypti genome contains 18 loci that encode putative Fox factors. Our stringent cladistic analysis has profound implications for the use of Fox genes as phylogenetic markers. Twelve Ae. aegypti Fox genes are expressed within various tissues of adult females, six of which are expressed within the fat body. All six Fox genes expressed in the fat body displayed dynamic expression profiles following a blood meal. We knocked down the 'fat body Foxes' through RNAi to determine whether these 'knockdowns' hindered amino acid-induced vitellogenin gene expression. We also determined the effect of these knockdowns on the number of eggs deposited following a blood meal. Knockdown of FoxN1, FoxN2, FoxL, and FoxO, had a negative effect on amino acid-induced vitellogenin gene expression and resulted in significantly fewer eggs laid. Our analysis stresses the importance of Fox transcription factors in regulating mosquito reproduction.
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http://dx.doi.org/10.1016/j.ibmb.2007.05.008DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2441594PMC
September 2007

Fz2 and cdc42 mediate melanization and actin polymerization but are dispensable for Plasmodium killing in the mosquito midgut.

PLoS Pathog 2006 Dec;2(12):e133

Institut de Biologie Moléculaire et Cellulaire, UPR9022 du CNRS, Equipe Avenir INSERM, Strasbourg, France.

The midgut epithelium of the mosquito malaria vector Anopheles is a hostile environment for Plasmodium, with most parasites succumbing to host defenses. This study addresses morphological and ultrastructural features associated with Plasmodium berghei ookinete invasion in Anopheles gambiae midguts to define the sites and possible mechanisms of parasite killing. We show by transmission electron microscopy and immunofluorescence that the majority of ookinetes are killed in the extracellular space. Dead or dying ookinetes are surrounded by a polymerized actin zone formed within the basal cytoplasm of adjacent host epithelial cells. In refractory strain mosquitoes, we found that formation of this zone is strongly linked to prophenoloxidase activation leading to melanization. Furthermore, we identify two factors controlling both phenomena: the transmembrane receptor frizzled-2 and the guanosine triphosphate-binding protein cell division cycle 42. However, the disruption of actin polymerization and melanization by double-stranded RNA inhibition did not affect ookinete survival. Our results separate the mechanisms of parasite killing from subsequent reactions manifested by actin polymerization and prophenoloxidase activation in the A. gambiae-P. berghei model. These latter processes are reminiscent of wound healing in other organisms, and we propose that they represent a form of wound-healing response directed towards a moribund ookinete, which is perceived as damaged tissue.
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http://dx.doi.org/10.1371/journal.ppat.0020133DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC1757202PMC
December 2006

Identification of two cationic amino acid transporters required for nutritional signaling during mosquito reproduction.

J Exp Biol 2006 Aug;209(Pt 16):3071-8

Center for Disease-Vector Research, Department of Entomology and the Institute for Integrative Genome Biology, University of California Riverside, 3401 Watkins Drive, Riverside, CA-92521, USA.

The defining characteristic of anautogenous mosquitoes is their requirement for a blood meal to initiate reproduction. The need for blood drives the association of vector and host, and is the primary reason why anautogenous mosquitoes are effective disease vectors. During mosquito vitellogenesis, a key process in reproduction, yolk protein precursor (YPP) gene expression is activated specifically in the fat body, the insect analogue of the vertebrate liver. We have demonstrated that blood meal derived amino acids (AAs) activate YPP genes via the target of rapamycin (TOR)-signal transduction pathway. Here we show, by stimulating fat bodies with balanced AA solutions lacking individual AAs, that specific cationic and branched AAs are essential for activation of the vitellogenin (vg) gene, the major YPP gene. Treatment of fat bodies with AA uptake inhibitors results in a strong inhibition of AA-induced vg gene expression proving that an active transport mechanism is necessary to transduce the AA signal. We identified two cationic AA transporters (CATs) in the fat body of Aedes aegypti females--Aa slimfast and iCAT2. RNAi knockdown of slimfast and iCAT2 results in a strong decrease in the response to AAs by the vg gene similar to that seen due to TOR inhibition. These data demonstrate that active uptake of specific AAs plays a key role in nutritional signaling during the onset of vitellogenic gene expression in mosquitoes and it is mediated by two cationic AA transporters.
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http://dx.doi.org/10.1242/jeb.02349DOI Listing
August 2006

Complement-like protein TEP1 is a determinant of vectorial capacity in the malaria vector Anopheles gambiae.

Cell 2004 Mar;116(5):661-70

European Molecular Biology Laboratory, Meyerhofstrasse 1, 69117 Heidelberg, Germany.

Anopheles mosquitoes are major vectors of human malaria in Africa. Large variation exists in the ability of mosquitoes to serve as vectors and to transmit malaria parasites, but the molecular mechanisms that determine vectorial capacity remain poorly understood. We report that the hemocyte-specific complement-like protein TEP1 from the mosquito Anopheles gambiae binds to and mediates killing of midgut stages of the rodent malaria parasite Plasmodium berghei. The dsRNA knockdown of TEP1 in adults completely abolishes melanotic refractoriness in a genetically selected refractory strain. Moreover, in susceptible mosquitoes this knockdown increases the number of developing parasites. Our results suggest that the TEP1-dependent parasite killing is followed by a TEP1-independent clearance of dead parasites by lysis and/or melanization. Further elucidation of the molecular mechanisms of TEP1-mediated parasite killing will be of great importance for our understanding of the principles of vectorial capacity in insects.
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http://dx.doi.org/10.1016/s0092-8674(04)00173-4DOI Listing
March 2004